1. Field
The present application relates in certain embodiments to prosthetic devices. In particular, the present application in certain embodiments relates to a frictionless vertical suspension mechanism for a prosthetic foot.
2. Description of the Related Art
Prosthetic feet of different designs are well known in the art. The various conventional designs have sought to solve various limitations associated with prosthetic feet.
Some prosthetic foot designs employ shock absorbing members (e.g., ankle members). However, such shock absorbing members tend to be relatively heavy and/or bulky. A common problem observed in prosthetic feet aiming for high travel suspension is that when in mid-stance, the bodyweight is supported by both the toe and the heel, but at heel strike or toe-off the weight is only supported by the respective part of the prosthetic foot. Therefore, the foot will be significantly stiffer at mid-stance than at heel strike or toe-off. This can cause an “obstacle” like feeling in the mid-stance of the rollover of the foot. Existing prosthetic feet with vertical suspension shock absorbers are also heavy with relatively high energy losses from, for example, the foot hitting the ground and friction within the suspension system, and are therefore arguably not well suited for high active use, such as running.
Accordingly, there is a need for an improved shock absorbing member for a prosthetic foot that is lightweight and provides frictionless vertical suspension regardless of the direction of the force on the prosthetic foot, and a need for a prosthetic foot incorporating the improved shock absorbing member that has rollover characteristics fit for everyday use and that encourages highly active use (e.g., running) through its suspension, energy return and light weight.